The present invention relates to display racks and the like of the type which are assembled by suitably interconnecting a plurality of vertical and horizontal members and, more particularly, to a device for facilitating the locking engagement of the vertical and horizontal members in such an assembly.
Display racks and the like which are assembled by suitably interconnecting a plurality of vertical and horizontal support members to form a multiple shelf rack assembly are commonly used for supporting and displaying various types of articles both in commercial establishments and in private homes. Such rack assemblies are typically provided in a "knocked-down" form and assembled by the user to satisfy his or her particular requirements, which requirements depend upon the amount of desired storage capacity as well as the space available in which to assemble the unit. The vertical and horizontal members are typically interconnected by a cooperating hook and slot arrangement which prevents disassociation of the members in a horizontal direction. In order to prevent vertical disassociation of the members a locking device is often provided in an attempt to fixedly and securely maintain the hook and slot connection. Prior art locking devices designed for this purpose have not, however, proven to be altogether satisfactory. In particular, some of the disadvantages associated with these prior art locking devices include the use of relatively complex and therefore costly mechanical locking arrangements, the use of locking devices which are difficult for an untrained person to install and the use of locking devices which do not provide a suitably secure connection. In addition, known prior art locking devices are not adapted for securing hook and slot connections wherein the longitudinal dimensions of the slots are variable.
One typical prior art technique for securing the tongue or hook and slot connection has been the use of pivotally mounted locking members. For example, U.S. Pat. No. 3,601,432 to Fenwick discloses the use of a pivotal member for inserting a locking tab into the slot in order to prevent the hook from being withdrawn therefrom. Other examples of pivotally operable locking devices are disclosed in U.S. Pat. Nos. 4,048,768, and 4,154,419 to Good and Breidenback respectively. The use of spring-biased locking devices is also known in the art as exemplified by U.S. Pat. Nos. 3,680,711 and 3,697,034 to Brucker and Shell respectively. U.S. Pat. No. 1,008,720 to Knape teaches a locking device having a projection slidably insertable within the slot opening above the mating hook for preventing withdrawal thereof from the slot. Other prior art locking devices are disclosed in U.S. Pat. Nos. 3,456 and 3,356,328 to Sunasky and Sachau respectively.